Coumarins from Phebalium tuberculosum ssp. megaphyllum and Phebalium filifolium.

A total of 14 coumarins have been isolated from the aerial parts of Phebalium tuberculosum ssp. megaphyllum and 9 from Phebalium filifolium (Rutaceae). Three of the coumarins obtained from P. tuberculosum ssp. megaphyllum are novel and have been characterized, on the basis of spectroscopic analysis, as (E)-7-(6-hydroperoxy-3,7-dimethylocta-2,7- dienyloxy)coumarin [3], (E)-8-(6-hydroperoxy-3,7-dimethylocta-2,7-dienyloxy)psoralen [16] and (E,E)-8-(7-hydroxy-3,7-dimethylocta-2,5-dienyloxy)psoralen [15] In addition, both species yielded the simple acetophenone xanthoxylin, and P. tuberculosum ssp. megaphyllum gave (E)-betulin-3-p-coumarate [20] and (Z)-betulin-3-p-coumarate [21], both of which appear to be novel. The chemotaxonomic implications of coumarin distribution in the two species are discussed.